The One Where No One Proposes - S9-E1
Revealing mistake: While everyone's looking at Emma through the window, when Jack makes the comment about the first grandchild, someone in the background walks by and causes the hallway's set wall to wobble behind them.
The One Where No One Proposes - S9-E1
Revealing mistake: When the nurse hands Emma to Rachel, you can tell it's not a real baby. (00:08:10)
The One Where No One Proposes - S9-E1
Revealing mistake: When Rachel is breastfeeding Emma for the first time, the baby's head is constantly moving in the same repetitive pattern suggesting it is one of those life-like dolls. Babies do not move their heads like that. (00:08:20)
Answer: Usually by the seventh night of Hanukkah you don't know what to get the other person, and you will probably resort to getting the other person something insignificant. Chandler is basically saying that the pen is a stupid gift.